Firebox construction



March 17, 1953 H. MILLER FIREBOX CONSTRUCTION 4 Sheets-Shea?I 2 Filed April 16, 194'? March 17, 1953 H. L. MILLER FIREBox CONSTRUCTION 4 Sheets-Sheet 3 Filed April 16, 194'? JNVENToR. HOM/APD LMI/.Lee

March 17, 1953 H. MILLER 2,631,574

FIREBox CONSTRUCTION Filed April 16, 194'? 4 Sheets-Sheet 4v MEML IN VEN TOR.- HOWARD L M/l. L E@ Patented Mar. 17, 1953 FIREBOX CONSTRUCTION Howard L. Miller, Cleveland Heights, Chio, as-

signor to Republic Steel Corporation, Cleveland, Ghia, a corporation of New `lersey Application April 16, 1947, Serial No. 741,741

6 Claims.

This invention relates generally to boilers and more specifically to the construction of firewalls and crown sheets for boiler reboxes, particularly those employed in locomotive and marine type boilers, and a novel method of making such devices.

For over a century boilers of the type to which this invention relates have had reboxes formed of inner and outer metal sheets stayed together against pressure between the sheets by stay bolts. These bolts have been applied by drilling or punching holes in the inner and outer sheets, tapping these holes, inserting threaded stay bolts therethrough and riveting the'heads over. It has also been customary to employ threaded bolts and to tap the inner sheets as an additional holding means using ball end flexible bolts in the outer sheets. The inside sheet of the rewall and the crown sheet are heated by the re within the rebox causing expansion of the inner sheet. Also, steam under high pressure is present in spaces between the inner and outer sheets tending to separate the inner sheet and outer sheet and stretch the stay bolts. As a result, when the boiler cools down the inner sheet and the stay bolts contract and distort which tends to pull the sheet away from the'stay bolts and loosen the joints around the stay bolts'. This results in leakage around the stay bolts and it is not vuncommon for the sheets themselves to develop fatigue cracks at the stay bolt holes causing failure and necessitating replacement of sheets.

It is an object of the present invention to provide a iirewall construction and a crown sheet construction which will not be subject to excessive deformation or failure in use and which will not leak due to expansion and contraction of the parts. Briefly, I attain these results in a novel rewall construction by building up the rewall from structural members in such a man ner that no stay bolts are required in areas of the assembly subjected to the heat of the fire, the inner wall being imperforate. I have found that one effective method of making such a wall resides in forming a series of rewall elements -from structural membersl such as I beams. In 'this construction apertures are punched in the webs ofv the I beams for water circulation, and the flanges of the I beams are Welded together edge to edge to form a continuous wall. The I beams are vertically disposed and the upper end of the rewall so formed isv welded to the crown sheet structure.

Generally speaking, I make a novel crown sheet by severing thewebs of I beams to form longitudinal-members of'T cross-section, or preferably by utilizing rolled section oi T formation. I then weld stay bolt anchoring means to the vertical legs or webs of the T sections and weld anges edge to edge to form a continuous crown sheet iirewall. A rebox made according to these principles is highly resistant to deformation and deterioration due to action of the heat, has no tendency to leak due to loosening around the apertures for the stay bolts and is of generally superior and long lasting construction.

Another object lies in the provision of a re- Wall made according to the general principles outlined above but of tapering cross-section to provide a smooth juncture With the crown sheet and roof sheet.

Still another object of my invention resides in the provision of novel and effective means for anchoring stay bolts to the crown sheet without requiring piercing of the crown sheet.

A furthe-r object of my invention resides in the provision of a rebox which has the inner wall formed of heat resistant metal such asA ferritic chrome steel and the outer wall oi a more economical metal such as mild steel or structural steel, the structure being made in accordance with the principles outlined above and being relatively economical to manufacture.

These and other objects of my invention will be apparent to those skilled in the art as the following description proceeds.

In the drawings:

Fig. 1 is a longitudinal section through a locomotive rebox embodying a preferred form of my invention;

Fig. 2 is a fragmentary perspective view of a rewall made in accordance with a preferredl form of my invention;

Fig. 3 is a partial cross-section through a i'lrebox produced in accordance with the preferred form of my invention;

Figs. 4 to 7 show means employed for attaching stay bolts to the crown sheet in accordance with my invention;

Fig. 8 is a partial cross-section through a rebox showing a modied form of firewall that is tapered and merges with a curved crown sheet section constructed similarly to the firewall;

Fig. 9 is a modi-ed form similar to that shown in Fig. 8l except that the firewall is not tapered;

Fig. I0 is a modied form showing: a modified crown sheet section joined to therewall;

Fig. 1l illustrates a form similar to that shown in Fig. 9 wherein the structural member rewall and crown sheet section are welded to a conventional crownsheet and roof sheet; and

Fig. 12 illustrates a fragmentary section aeeitvfithrough a composite firewall wherein the elements exposed to the fire are heat-resistant metal.

Referring to Fig. l, which is a simplified section through a locomotive boiler illustrating the over-all relationship of my novel firewall, radius sheet and crown sheet, the boiler B includes the crown sheet C, the radius sheet R, and the firewall W which units are joined together as will be hereinafter described. The lower edge of the rewall is welded to the foundation ring @il and the lateral elements il of the ring form the foundation for the back boiler head l2 and the throat sheets i4. rI'he roof sheet I3 is preferably of conventional construction as is the back tube sheet l5.

As shown in Figs. 2 and 3, the firewall W made in accordance with the principles of this invention is formed from a plurality of vertically disposed structural channel members 2% preferably formed from I beams. In order to provide for water circulation I out or punch out a series of apertures 22 in the webs of the I beams. The remaining portions of the initially imperforate web form a series of webs 23 that provide integral tie members between the two flanges. I then weld the flanges of the I beams together edge to edge as at 2S and I prefer' to employ a backing plate 25 previously tacked on to one of the I beams before the welding operation. The lower edges of each flanges are welded to the foundation ring ii! as at 26 and 2l, and in order to reinforce the structure at this junction one row of stay bolts 28 may be provided. I may attach the upper Vedge of the rewall so formed to the radius sheet R, by welding as at 33. I form the I beams to provide an extension 29 at the outer wall which I weld to the roof sheet i3 as at 32. In this manner the lower stay bolt 3l for the radius sheet passes through an aperture 3@ in the outer portion of the firewall and serves to additionally hold these parts together against pressure between the walls.

A firewall formed in this manner does not rely upon stay bolts to maintain the parts in assembled relation against pressure and high heat so that the expansion due to heating and cooling will not cause leaking. The single row of stay bolts 28 adjacent the foundation ring Il) is below the grate surface, consequently these bolts are always covered with water and will cause no trouble. The web portions 23 are integral with the inner and outer walls, and serve not only to resist wall separation but serve to rigidly maintain the inner wall in position relative to the outer one and prevent deformation and distortion in service.

The neutral axis of the remaining webs 23 are provided with through apertures or telltale holes 23d. Not only do these apertures increase the heat transfer to the water, but if one or more of the remaining webs 23 fracture at the welds or otherwise, such fracture will be indicated by leakage of water or escape of steam from within the fire wall.

A preferred form of a crown sheet C, radius sheet R and stay bolt assembly is shown in Figs. 3 to 7. To produce the crown and radius sheets I use a plurality of T-shaped sections or beams 40. The webs are then slit as at il to provide a plurality of Vgenerally radially extending ears 42. In the form shown in Figs. i and stay bolt anchors or sockets are welded to ears 42. I prefer to form the anchor in the form of a neck member 43 welded to each ear and an integral socket member 44 for receiving the threaded shank of a stay bolt 45. The stay bolt is adjustably tensioned against the roof sheet i3 by means of a nut assembly 46 which provides a seal and tensions the bolt. The details of the construction of the assembly 46 may be varied in accordance with standard practice and form no part of the present invention.

A modified form of attaching means for the stay bolt is shown in Figs. 6 and 7 wherein a pair of ears 5i? are assembled in a slot 5I in the shank of each stay bolt 45, the ears forming a clevice for encompassing the ears 42 of the crown sheet web. Bolts or other fasteners 52 may be employed to secure the stay bolts to the crown and radius sheet web. A crown and radius sheet so manufactured is imperforate and shows no tendency to leak or deform in service. By slotting the webs as at 4l to form the ears 42 I provide a degree of fiexibility and also insure that each stay bolt assumes its share of the load.

If a water firewall which gradually increases in thickness from the foundation ring to the junction which the crown sheet is desired, I may employ the structure shown in Fig. 8. The I beam members d of the rewall W have a tapered piece removed from the web 62 whereupon the webs are `welded together as at 63 to provide a rewall of generally tapered crosssection. When the spacing between the inner and outer walls exceeds the depth of the I beam to be employed in the construction, I sever the webs'of I beams 6I to form sub-members the flanges of which are to be inner and outer walls 65 and 66 and weld to the severed web sections a plurality of gusset plates 61 to form composite members, the gussets being dimensioned so that the firewall merges smoothly 'with the radius sheet R and crown sheet C and the roof sheet E3. After these web sections have been severed and the severed webs have been welded together, apertures are cut in the resultant composite web for water circulation through the firewall. T sections of suitable size may replace one of the sub-members. The radius sheet section thus formed is welded to the tapered firewall section as at 69, to the roof sheet as at l@ and the crown sheet formed of longitudinal members 40 as at 1i.

The form shown in Fig. 9 has the radius sheet section R formed of gusseted I beams or T sections like that shown in Fig. 8 but employs the parallel side wall firewall W formed of I beams 2E! similar to that described in connection with Fig. 3. In the constructions just described no stay bolt is employed where the crown sheet is welded to the firewall.

In the form shown in Fig. 10, crown sheet C is welded as at I4 to a modified radius sheet section 75. This includes a plurality of transversely extending members of the T section l, the webs of which are slit to provide ears l1 for the attachment of stay bolts 'i8 and the lower end thereof welded to the firewall W as at 79. This provides an effective means of joining the crown sheet to the firewall. The edges of the T-shaped members 'I6 are welded together to present an imperforate wall to the nrebox as described in connection with the assembly of members 4@ of the crown sheet.

Fig. l1 shows a modified form wherein the straight walled members 20 forming the rewall W are welded as at 69 to the gusseted I beam o r T members 65 and 66 similar to the tion 80 is employed and is welded to the radius sheet section as at 8|. The roof sheet is welded to the ange on member 66 as at 82. The

gusseted radius sheet section here serves to strengthen the roof section of the firewall because of its rigid and non-distortable construction,

It is desirable to form the walls that are subjected to the heat of the re of a heat-resistant like. However, this steel is relatively expensive ascompared to the cost of mild steel and in Fig. 12 I show a composite firewall structure wherein the advantages of heat resistance and economy are combined in onerstructure. To produce the firewall illustrated in Fig. 12, I sever the webs Vof one set of structural members such as I beams -members lare welded to the severed webs 93 of the rebox steel members as at 94. Then the edges of all flange members of the composite I beams so formed are Welded together as at 95 with the heat-resistant elements all welded together. This forms a firewall of rigid imperforate construction like that previously7 described but since only the inner wall need be of heat-resistant material there is a great saving in cost. Of course, the composite webs formed in this manner may be perforated as previously described for water circulation.

I contemplate that the composite structure shown in Fig. 12 may be adapted to the assemblies illustrated in the other figures. Although I prefer to employ I beams as the elements of the rewall and crown sheet construction, I could form firebox elements having characteristics like that described by severing the Webs of channel irons or utilizing T sections and welding the iianges together edge to edge.

Unless otherwise qualified, the terms channel member or channeled members as found in the specification and claims is intended to include any structural member having opposed -anges joined by a web which member can be used to practice the invention, such as C-shaped channel irons, I-beams, H-beams, and the like. All of these elements are characterized by a structure involving opposed flanges joined by a web and obviously all may be employed to practice the broader aspects of the invention.

I contemplate that special structural shapes may be rolled for use in my construction. For example, an I beam could be rolled having one flange thicker than the other, which ange would then be employed as the outer ange or wrapper sheet of the firewall without materially increasing the weight.

These and other modifications may be made without departing from the spirit of my invention and I contemplate that I do not wish to be limited to the illustrated embodiments except as may be set forth in the appended claims.

What is claimed is:

1. The method of forming Ia unitary firebox section for a boiler comprising longitudinally severing the webs of a set of channeled structural steel members, severing the webs of a second set of channeled members composed of heat resistant steel, welding the resulting severed webs of one set of members to the corresponding severed Webs of the other set, forming apertures in the resultant composite web for water circulation, and welding the flanges of each set together to form a firewall.

2. The method of making a boiler Wall cornprising the steps of severing the webs of chanmetal such as boiler steel, iirebox steel or the y neled members to form sub-members, disposing gussets between opposed edges of the severed webs of opposed pairs of sub-members, welding the gussets to said opposed web edges to form composite members, aperturing the webs of said composite members, and welding the fianges of lsaid composite members together edge-to-edge.

3. In a boiler, a unitary firewall section built of paired elongated elements, each pair of elements comprising inner and outer spaced and parallel members forming a hollow wall portion, each member having web means extending perpendicularly with respect to the member but interiorly with respect to the wall portion, the web means of each said pair being welded together edge-to-edge, with the exterior sides of said paired elements facing oppositely to form composite channel members with interior and exterior wall surfaces, said inner members being welded together edge-to-edge and said outer members being welded together edge-to-edge to form the firewall section, said firewall section having a plurality of tell-tale holes, said holes extending thru both members of a pair and thru the associated web means whereby fracture of the web means will be indicated by escape of fluid from within said rewall and through said holes.

4. In a boiler, a rst wall section built up of generally vertically disposed paired elongated elements, each pair of elements comprising inner and outer wall portions and connecting members, the inner wall portions being welded together edge-to-edge, a second wall section formed of a second series of vertically disposed wall portions having curved, spaced, diverging inner and outer flanges and integral web members, gussets welded between said web members, said curved flanges being welded together edge-to-edge to form a leak-proof wall, said second series of elements being end welded to form a continuation of said wall vertical section, and a third section Welded to said second section and comprising a plurality of elongated elements, said last-mentioned elements having inner anges welded together edge-to-edge to form a wall, integral web means extending outwardly from said last mentioned flanges, an outer sheet spaced from said last mentioned wall and a plurality of stay bolts extending between said web means and said outer sheet, the elements of said third section being transversely disposed relative to those of said other sections.

5. In a boiler, a curved wall section formed of a series of generally vertically disposed elements having curved, spaced, diverging inner and outer anges and integral web members, gussets welded to and between said web members, said curved fianges being welded together edge-to-edge to form a leak-proof wall, and another wall section welded to said curved wall section and comprising a plurality of elongated members, each elongated member having an inner flange welded together edge-to-edge to the inner flange of an adjacent elongated member to form an inner wall, integral web means extending outwardly from the adjacent flanges of said elongated mem- 7 bers, an outer sheet spaced from said inner wall, and a plurality of stray bolts extending between said web means and said outer sheet, the elongated members of said other section being disposed perpendicular to the generally vertically disposed elements of said curved section.

6. In a boiler, a curved wall section comprising a plurality of relatively straight, elongated elements, each element having an inner flange and an integral outwardly extending web, said flanges being welded together edge-to-edge to form an inner wall, an outer sheet spaced from said inner wall, a plurality of stay bolts extending between said web and said outer sheet, the members of said wall section being longitudinally disposed with respect to the boiler.

HOWARD L. MILLER.

REFERENCES CITED The following references are of record in the le of this patent:

Number 8 UNITED STATES'PATENTS Name Date Bryan Dec. 18, 1877 Heuer Oct. 13, 1891 Livingstone May 7, 1907 McClellon July 28, 1914 OBrien Feb. 16, 1915 Ducas Mar. 21, 1916 Flannery et al Julyv27, 1920 Ducas Sept. 21, 1920 Leghty Feb. 22, 1921 Bushong Aug. 3, 1926 Murray et al Mar. 29, 1927 Pilcher et al Nov. 26, 1929 Laufle Sept. 19, 1933 Rothenstein May 21, 1935 Murray Sept. 2l, 1937 Goddard July 5, 1938 Hawley Jan. 9, 1940 Murray Nov. 12, 1940 Huston et al Dec. 17, 1946 

